1. Field of the Invention
The present invention relates to a thermoplastic polyester resin composition. More particularly, it relates to a thermoplastic polyester resin composition which is quickly crystallizable and comprises a specific crystallization accelerator in a thermoplastic polyester.
2. Description of the Prior Arts
Thermoplastic polyesters especially polyethyleneterephthalate are important as raw materials for preparing fibers, films and molded products. The thermoplastic polyesters have excellent characteristics such as high wearing resistance, excellent creep property and high dimensional accuracy because of partial crystalline structure. Therefore, thermoplastic polyesters are especially suitable for molded products to which severe mechanical stress is applied or which is heated at severe condition. Polyethyleneterephthalate, however has slow crystallization velocity requires relatively high temperature of a mold (about 140.degree. C.) and relatively long time for pressing in preparation of a molded product. This is disadvantageous when preparing a molded product by an injection molding process.
Polybutyleneterephthalates have been commonly used as polyester resins for molding because of high crystallization velocity thereof. If the crystallization velocity is further increased, the molding cycle can be shortened to reduce production cost. This is remarkable advantage.